Polyfluoroalkylsulfonamido alkyl amines are useful starting materials for various products including: fluorinated surfactants, including cationic, non-ionic, anionic, and amphoteric surfactants, and fluorinated repellents, including poly-(meth)acrylamides, ureas, imides. Specific applications for the products made from polyfluoroalkylsulfonamido alkyl amines include: electronics applications, nanotechnology, pharmaceutical and pesticide intermediates, catalysts, and firefighting foaming agents.
Conventional methods for making polyfluoroalkylsulfonamido alkyl amines typically provide low yields and produce an undesirable fluorine containing by-product which represents an economic loss. For example U.S. Pat. No. 4,486,391 contemplates making polyfluoroalkylsulfonamido alkyl amines by reacting a polyfluoroalkylsulfonic compound with a diamine as represented by the following:CF3(CF2)5—S(O)2—Cl(polyfluoroalkylsulfonic acid halide)+H2N—(CH2)3—NH2(diamine)→CF3(CF2)5—S(O)2—NH—(CH2)3—NH2(polyfluoroalkylsulfonamido alkyl amine)+CF3(CF2)5—S(O)2—NH—(CH2)3—NH—S(O)2—CF3(CF2)5(bis-sulfonamide by-product).
Like other conventional methods, U.S. Pat. No. 4,486,391 provides a synthetic route requiring a diamine reagent that, by definition, has two reactive amine sites per molecule, both of which can be converted to sulfonamido groups thereby forming a bis-sulfonamide by-product, which is also described in the GB patent 1,378,984. Conventional methods fail to disclose a synthetic route to a polyfluoroalkylsulfonamido alkyl amine that avoids the production of a bis-sulfonamide by-product, an undesirable impurity that typically worsens surfactancy, foaming properties, or other performance characteristics of desired products made from the polyfluoroalkylsulfonamido alkyl amine. Furthermore, the bis-sulfonamide by-product shares very similar physical properties with the desired polyfluoroalkylsulfonamido alkyl amine thus making its isolation and purification difficult and costly. In general, the bis-sulfonamide by-product constitutes a substantial loss of costly fluorinated starting material instead of the efficient incorporation of fluorine to make the desired polyfluoroalkylsulfonamido alkyl amine.
Because of the aforementioned disadvantages, it would be desirable to discover a method for making a polyfluoroalkylsulfonamido alkyl amine that avoids the use of a diamine reagent and the concomitant production of a bis-sulfonamide by-product.